title: Laboratory scale examination of the effects of overloading on the anaerobic digestion by glycerol.
abstract: The anaerobic digestion of pure glycerol, which produces a baseline acetic acid to propionic acid ratio of 0.2, was studied in laboratory scale reactors (3 l working volume) at mesophilic temperature (37 °C) with 3000 mg chemical oxygen demand (COD)l(-1) d(-1). During the experiment tVFA and C2-C6 VFA analysis and daily biogas yield measurement were carried out. Following 10 days of a 15% d(-1) increase in the organic loading rate (OLR) of 3.0-10.5 g COD l(-1) d(-1), the concentration of propionic acid increased to 6200-8000 mg l(-1). Then the inoculum was divided into three parts feeding with 100% glycerol, 50% glycerol + 50% acetic acid, and 50% glycerol + 50% thick stillage, (presented in % of 2.60 g COD l(-1) d(-1) OLR), respectively. The application of co-substrates reduced the recovery period by 5 days compared to feeding with pure glycerol. When the reactors were loaded with glycerol again (10% OLR raise per day) the previously applied co-substrates had a positive effect on the VFA composition and the biogas yield as well.
authors.affiliation: Faculty for Forestry, Institute of Chemistry, University of West Hungary, H-9400 Sopron, Bajcsy-Zs u4, Hungary. tretfalvi@emk.nyme.hu
authors.forename: Tamás
authors.initials: T
authors.lastname: Rétfalvi
authors.forename: Annamária
authors.initials: A
authors.lastname: Tukacs-Hájos
authors.forename: Levente
authors.initials: L
authors.lastname: Albert
authors.forename: Béla
authors.initials: B
authors.lastname: Marosvölgyi
mesh_terms: D000693:Anaerobiosis; D005285:Fermentation; D005990:Glycerol / Q000737:chemistry*
chemical_list: D005990:Glycerol